1. Field of the Invention
The present invention relates to a technique for supporting a payload in the cargo bay of a space vehicle. The payload is supported in part by a plurality of radially adjustable pads which are attached to a cradle assembly which is in turn attached to the frame of the space vehicle. Each pad includes an elastomeric covering whereby lateral loads are transferred from the payload to the cradle and to the frame of the space vehicle.
2. Brief Description of the Prior Art
The prior art discloses several techniques fior securing a payload to a cradle in the cargo bay of a space vehicle. In U.S. Pat. No. 4,044,974, for a "Closed Cradle Space Vehicle Support and Deployment System," issued on Aug. 30, 1077 to Lingley, et al., the cradle is attached to the spacecraft by two pairs of continuous, outwardly extending rings called continuous integrated normal clamping hook (CINCH) rings. One pair of rings is located at the forward edge f the spacecraft and the other at the aft end of the spacecraft. The CINCH rings are mounted on the inner surface of the cradle and mate with spacecraft interface rings that are located around the circumference of the spacecraft. The forward CINCH ring has a concave surface section which mates with a correspondingly shaped convex surface on the forward spacecraft interface ring. This connection reacts in longitudinal (X) and radial (Y,Z) directions. The aft CINCH ring has the shape of a trough. An aft spacecraft interface ring abuts against the aft CINCH ring and reacts against only radial (X,Y) loads.
While the use of continuous sectiions in the Lingley device helps to minimize the maximum moment which is transmitted to the cradle and permits some minor rotation of the payload, thus further reducing the design moment of the cradle, the Lingley device also has certain disadvantages. One disadvantage of the Lingley device is that the rings are designed for cylindrical payloads. If a payload is not cylindrical, e.g., square, special rings and a supporting structure must be fabricated for the cradle and the payload.
A second disadvantage is that the two continuous rings in the Lingley design generate extra weight. The weight added by the two rings which are attached to the payload which is to be deployed into space is especially undesirable.
A third disadvantage is that, while the Lingley design permits some rotation of the payload, it restricts forward and aft movement. This restriction increases the loads that are transferred to the cradle and necessitates a heavier cradle design.
In U.S. Pat. No. 4,290,570, issued on Sept. 22, 1981 to Smolik, et al, for a "Three Point Attachment For An Ejectable Spacecraft," a spacecraft is attached to a cradle at three points. Each connection is made by a bal and socket type connection. At two of the three points, the ball and socket connection is made by means of a locking mechanism attached to the cradle which drives a bar through holes in the ball and holes in the swivel joint which serves as a socket. At the third connecting point, the ball mounts into a locking mechanism which serves as the socket joint.
One disadvantage of the Smolik device is that locating all the connections between the payload and the cradle in a single plane limits the size of the payload. Heavier payloads require both forward and aft connections. Moreover, the locking mechanism and trunnion balls in the Smolik device add weight to the cradle and spacecraft, respectively, thus reducing the size of the payload. In addition, the use of only three connection points requires that the structure which transfers loads from the connection points to the orbiter be reinforced at those points. Additional connections between the spacecraft and the cradle would lessen those loads and reduce the size of the structure. Finally, the Smolik device is complex and may be difficult to install and operate.
Another support system is the design for the Inertial Upper Stage (IUS) prepared by Boeing. In the IUS, a payload consisting of an upper stage mated to a spacecraft is carried in the cargo bay of the orbiter of the NASA Space Transportation Systems (STS) by means of a tilting aft cradle and a forward U-shaped cradle. The payload is attached to the forward cradle by a pair of payload retention latch assemblies (PRLA). The PRLA are attached to the cradle by load levelers and the cradle is attached to the frame of the orbiter by low response hydraulic dampers. A motor driven gear train assembly in the PRLA closes a claw around a trunnion attached to the payload and seats the trunnion between a lower half spherical bearing and a top half spherical bearing in the PRLA.
The main disadvantage of the IUS device is that the moments generated by the movements of the spacecraft in the cradle are transferred to the cradle at only a few points. In order to resist these moments, the cradle structure must be reinforced at those points, creating additional weight. Another disadvantage of the IUS design is that it is complex because it requires the use of additional equipment e.g., dampers and load levelers. This equipment increases the weight of the cradle and the payload.
Accordingly, it is an object of the present invention to provide a means for attaching a relatively large payload to a cradle in a space vehicle.
It is a further object of the present invention to provide an attachment apparatus which transfers loads from the payload efficiently and effectively.
It is also an object of the present invention to provide a means for attaching a payload to the cradle of a space vehicle which minimizes the weight of the attachment apparatus.